Every year, dedicated scientists have the grim task of compiling a master list of climate calamities that have befallen Australia.
It’s a miserable chronicle of extreme events, but the scientists who put it together say it’s essential reading.
Because people forget, and forgetting is dangerous in the face of escalating climate threats that demand preparation.
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The annual State of Weather and Climate Extremes report is co-written by more than 30 scientists and researchers from the ARC Centre of Excellence for Climate Extremes.
The 2023 edition, released on Thursday, details 11 major disasters including extreme flooding in three states, vanishing Antarctic sea ice, a snow season that died early, metres of rain from a cyclone in Queensland, and fires that rolled into floods in a single week in Victoria.
It’s hoped packaging up key events in a digestible form will help people understand what’s happening in the environment, and think about how they can prepare for what lies ahead.
“What was unusual about 2023 is how intense some of these events were and how they kept pushing records,” centre director Andy Pitman says.
While it’s challenging to determine the cause of each extreme event, he says they seem to have occurred with increased frequency in 2023.
“Some of them were occurring one after the other or close to each other,” Pitman said.
“These temporally and spatially compounding events had a substantial impact on our environment and were difficult for us to deal with.”
Overall, 2023 was the eighth-hottest year on record in Australia, with temperatures almost 1C above the 1961-1990 average; winter was the warmest since records began in 1910, and September was the driest on record.
“What scientists bring to the table is more and more evidence of what we already know,” Pitman said.
“We need to act based upon observations and existing knowledge.”
He says that means halting carbon emissions, investing heavily in adaptation, and for everyday Australians, encouraging a focus on preparation.
11 Climate Calamities
The State of Weather and Climate Extremes 2023 report looks at 11 major incidents.
1. Ex-cyclone floods the Kimberley
For a fortnight into early 2023, ex-tropical Cyclone Ellie slowly moved across the Northern Territory and the Kimberley in Western Australia.
Rivers hit record heights and the Fitzroy beat the previous record by almost 2m. Dimond Gorge had 838.8mm of rain in 10 days, just shy of its annual average rainfall.
Damage was put at $322 million. Critical infrastructure was damaged, people were evacuated, communities were cut off and food was in short supply.
The report doesn’t attribute the cyclone to climate change but does not rule out warming as a factor. It says climate change could mean fewer cyclones for Australia, but a higher proportion of intense ones such as Ellie.
2. Floods in the NT and Queensland
In late February and early March, a persistent low-pressure system flooded remote communities in the Northern Territory and Queensland’s northwest.
It was long-lived and slow-moving, leading to incredible rainfall totals over several days.
Flooding in remote locations stretched emergency services, and three Indigenous communities were relocated to Darwin where people remained stuck for up to three months.
Transport routes were disrupted and there were food shortages.
Persistent monsoon lows are uncommon but not unheard of in Australia. The report notes numerous similar events, with work underway to better understand slow-moving, high-impact weather systems.
3. Winter heat in NSW
NSW and the city of Sydney notched up their warmest winters since records began.
In July, the temperature was about 3.5C higher than the long-term average.
Persistent high-pressure systems held off easterly winds that can bring rain. Unusual westerly and northwesterly winds also delivered warm, dry air.
Those large-scale weather patterns on top of background warming from climate change resulted in record-breaking temperatures, the report says.
It warns winters in southeast Australia will continue to warm and cool-season heat events will become more frequent and intense under climate change.
4. Snow season dies early
After a strong start, Australia’s snow season met an early end, with the nation’s warmest winter on record fuelling rapid snow loss in the Alps.
Global warming combined with natural weather systems and the result was fewer cold fronts that deliver snow, the report says.
September was extremely dry, and the hottest September on record in the Alps, and that delivered a savage blow for local economies that depend on the snow.
Poor snow seasons can’t yet be attributed to climate change but that doesn’t mean it wasn’t involved, the report says.
Snow depths have been steadily declining in past decades, while alpine temperatures rise.
5. South Australia’s September heatwave
A record heatwave with extreme temperatures 10C to 20C above average hit large parts of South Australia in mid-September.
Unseasonably high temperatures are part of a larger trend in southeast Australia, where heatwaves are becoming more frequent, more intense, and occurring earlier than usual due to climate change, the report says.
It warns of serious implications for human health, agriculture, and the environment.
6. Gippsland endures fires and floods in the space of a week
Early spring bushfires hit Victoria’s Gippsland region in October. When a low-pressure system arrived it put out the fires, but caused widespread flooding.
About 130 properties were flooded and the SES fielded hundreds of calls for help.
Future changes to the intensity and frequency of weather features that produce fire and flooding extremes are uncertain, and research is continuing.
7. Bushfires hit early in Queensland
More than 1000 bushfires broke out in Queensland at the end of October, marking an early start to the season.
The Western Downs region in the state’s southeast was hit hard, with more than 20,000 hectares burnt near the town of Tara.
Not only were the fires early, they were more persistent and continued to burn at night thanks to exceptionally hot and dry conditions, which the report notes will be more likely with climate change.
The fires also coincided with the return of El Nino and the driest September since 1900, which rapidly dried out vegetation growth during three preceding years of wetter La Nina conditions.
8. Rain-wind event lashes Hobart
Tasmania was hit by a slow-moving low-pressure system in October, dumping a month’s worth of rain over large parts of the state.
Another low packing extreme winds hit two days later, uprooting trees from rain loosened soil and wreaking havoc in the south, including Hobart.
A third system then delivered winds of 98km/h in Hobart, and 159km/h on Mt Wellington. The winds did much more damage than usual due to the soil being saturated.
More than 7000 properties lost power statewide, and properties, cars and other infrastructure were destroyed by falling trees.
The damage would have been far less if the events had not been back to back, the report says.
Researchers have found extreme winds-and-rain compound events will happen more frequently in many regions without effective action on climate change.
9. Hailstorm batters Queensland’s food bowl
A supercell thunderstorm brought heavy hail and extreme wind to Queensland’s Lockyer Valley in November.
One person died and damage to crops and farm equipment was estimated at $50 million.
The report notes severe thunderstorms are expected to be affected by climate change but it’s difficult to say exactly how.
A broad expectation is there’ll be fewer hailstorms overall, but larger hailstones when they develop.
Research continues into climate-related changes to severe thunderstorms and their associated hazards.
10. Cyclone Jasper hits far north Queensland
Category two Cyclone Jasper struck north of Cairns in mid-December, delivering torrential rain and flooding.
After crossing the coast it stalled over Cape York, contributing to a week-long deluge that inflicted major damage.
A large part of the far north recorded more than 400mm of rain. Some places copped over 2m.
The system caused major damage to roads, the power network, buildings, crops and closed the Cairns airport just before Christmas.
Research continues into the stalling of the system, something that also happened in February 2019, causing flooding in Townsville.
11. Antarctic sea ice hits record low
The extent of sea ice that surrounds Antarctica changes constantly. It grows during cooler months from March to September, before rapidly shrinking from October to February.
Scientists say climate change is having major impacts and in 2023, sea ice extent hit record lows in both winter and summer.
Sea ice still grew in the cooler months but much slower than in previous years.
The shift, from 2016 onwards, is consistent with climate change projections and aligns with warmer ocean temperatures.
The report warns a very low sea ice extent is unmatched in historical observations and has implications for the global climate system, including sea level rise.
